Overload release clutch for sewing machines



Aug. 5, 1947. F. PARRY Er AL l OVERLOAD RELEASE CLUTCH FOR SEWING MACHINES :5 sheets-snee; 1

Filed Jan. 15, 1946 N I// 74M@ 3 Sheets-Sheet 2 F. PARRY ET AL lOVERID' RELEASE CLUTCH FOR SEWING MACHINES Filed Jan. l5, 1946 Aug, 5., 1947.

.mg.5,1947.v RPARRYEETAL l' 2,425,120 y OVERLOAD RELEASE CLUTCH FOR SEWING MACHINES Filed Jan. l5, 1946 3 vSheets-Sheet 3 Patented Aug. 5, i947 UNITED lSTATES PATENT OFFICE f- OVERLOAD RELEASE CLUTCH FOR SEWING y MACHINES .Frank Parry and Berthold P. Pinkvoss, Bridgeport, Conn., assignors to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application January 15, 1946, Serial No. 641,233

13 Claims.

vmechanism in which the feed-dog is operated from actuating mechanism disposed below the work-support of the machine.

A further object of this invention is to provide a sewing machine with a compactly arranged actuating mechanism for a lower feed-dog of a Sewing machine having driving mechanism including an overload release clutch-for the rotary loop-taker of the machine,

More specifically, the present invention has for an object to provide improved'means for continuing in uni-son operation the needle and lower feeddog of a compound work-advancing mechanism in which the feed-dog is operated from actuating mechanism disposed below the work-support of a sewing machine and, upon overload, release of the sewing machine loop-taker from its driving mechanism.

Other and more specific objects of the invention will be apparent from the following description and claims.

The invention comprises the devices, combina view of the overload release clutch shown in Fig. 1.

Fig. represents an enlarged section taken substantially along line 5-5 of Fig. 1.

Figj6 represents an enlarged section taken substantially .along line 5-5 of Fig. l but illustrating the clutch in a disengaged position.

Fig. 7 represents a section taken substantially along line I-1 of Fig. 6. I

Referring more specifically to the drawings, the

2 machine having a frame including a work-'supporting cloth-plate or bed I0 and a bracket-arm secured to the bed and comprising a standard II and an overhanging arm I2, supporting at its free end a bracket-arm head I3. Journaled in bearings I4 and I5 and disposed lengthwise within the arm I2, is a main or needle-bar actuating shaft I6, carrying, at its rear end,4a combined belt and hand wheel I 'I having a.U-shaped annular groove I8 adapted to receive a driving belt by mean-s of which the shaft may be rotated from any suitable source of power.r

Secured upon the shaft I6, adjacent its rear end, is a grooved pulley I9 which through a clip- Ibelt 20 drives, in one-to-one ratio, a lower pulley and clutch drive 2| carried by a, lower rotary or bed-shaft 22 and sleeve 22.

Within the bracket-arm head I3 there is gmounted, for oscillation, a needle-bar frame 23 Also mounted in the head I3 is the usual springbiased presser-bar 32 which carries, at its lower end, a presser-foot 33. This presser-foot is adapted to hold the work on a throat-plate 34, and to cooperate with a serrated feed-dog, located beneath .the throat-plate, in the feeding of the work.

invention is disclosed as embodied in a sewing Cooperating with the needles, inI the formation of stitches, are two rotary loop-takers 35 locatedv bosses 4I and 42 in the lower end of the head I3.-

The needle-bar frame 23 isoscillated about the longitudinal axis of the rock-shaft 3.8, thereby to give to the needles 2l feed and return movements in timed relation with the movements of. the usual lower feeding mechanism hereinafter to be de.- scribed, by means of connections comprising a@ rock-lever 43 formed with a split lower end adapted to be clamped by a screw 44 to the rockshaft 38. The upper end of the lrock-lever 43 is operatively connected to one ,end lof a, pitman 45h;`

the other end of which is formed as a strap 46 which surrounds an eccentric 41 forming a part of an adjustable eccentric device, designated generally as 48, secured upon the arm shaftl. It will be understood that as the arm shaft is rotated, the eccentric 41 actuates the pitman 45, which in turn operates the rock-lever 43 to oscillate the needle-bar frame 23 about the axis of the rock-shaft 38. The extent of oscillatory motion imparted to the needle-bar frame, and thereby the amplitude of the feeding motion transmittedto the needles is dependent upon the amount of eccentricity of the eccentric 41. In

order to vary the amplitude of the oscillatory movements of the needle-bar frame to harmonize the same with the stitch length to which the lower feeding n iechanism is adjusted, the eccentric device 48 is so constructed that the eccentricity of the eccentric 41 may be adjusted between certain limits. Inasmuch as the details of construction of this adjustable eccentric device forms no part of the present invention, and furthermore as the same is disclosed completely in the U. S. patent of Myers, No. 2,128,031, dated Aug- 23, 1938, detailed illustration and'description thereof in this specification is deemed unnecessary. Sufce it to say that adjustment of the eccentric 41 is effected by relative rotation between the member 49 of the adjustable eccentric and the arm shaft I8.

For a more complete disclosure of the above noted needle-bar mechanism, reference may be had to the U. S. patent application of Frank Parry, Serial No. 599,059, filed June 12, 1945.

Below the cloth-plate I0, the machine is provided with a four-motion lower feeding mechanismincluding a feed-dog 50 having needle apertures 5U' and carried by a feed-bar 5| having a fork 52 engaged by a feed-lift eccentric 53 secured upon the shaft 22. At its forward end, the feed-bar is pivotally connected to a feed-rocker 54 secured upon a feed-drive rock-shaft 55 journaled in bearings .56 supported in bearing bosses 51 formed integral with the bed-plate I0. Upon unit, and the eccentrics 53. and 52 thereon, effects rising-and-falling and fee'd-and-return movements of the feed-bar 5I and the feed-dog 50 carried thereby. The construction ofthe adjustable eccentric device 63 on the sleeve 22', is the same as that carried by the arm shaft I6 which as above stated, is fully disclosed in U. S. Patent No.

2,128,031 and includes a member 49 which is rotatable relative to its supporting sleeve 22 to vary the eccentricity of the eccentric 82.

As illustrated in the drawings, the machine also includes means for providing a thread-clearance space between the nose of a thread-carrier, (not shown) forming a part of each of the loop-takers 35, and stop-lugs (not shown) provided by the throat-plate 34 supported by the bed I0. This mechanism forms no part of the present invention and therefore detail illustration anddescriptionl thereof is deemed unnecessary for this disclosure. Portions of the mechanism, however, are designated generally as X.y

Providedin this machine is means for simultaneously and synchronously varying the eccentricity of the upper feed-drive eccentric 41 and the lower feed-drive eccentric 62. This means is Patent No. 2,128,031,

disclosed in a pending patent application of F. Parry, Serial No. 599,059, led June 12, 1945, and comprises a, manually oscillatable rock-shaft 54 journaled in bearings 65 and 8B formed in the arm I 2. end thereof and by a set screw 61, is an outwardly projecting hand-lever: in the form of a crank 88 which projects through an opening (not shown) formed in the forward wall of the standard Secured upon the shaft 84, adjacent the bearings 65, is an arm 69 having an offset nger 10 adapted, upon the turning of the shaft 84 in one direction, to enter an aperture or notch 1| formed in the periphery of the member 49 of the upper adjustable eccentric 48.

Intermediate its ends, the hand-lever 68 is pivotallyconnected, at 12, to the upper end of a vertically disposed link 13, located mainly within the machine standard The lower end of the link 13 is pivotally connected, at 14, to the free end of a rock-arm 15 carried by one endof a rock-shaft 16 journaled, parallel with the shaft 64, in bearing bosses 'I1 depending from the cloth-plate l0.' Fixed to the other end portion of the rock-shaft 16, is an arm 18 having an offset finger 19 adapted,'upon turningof the rock-shaft in one direction, to enter an aperture or notch 1| in theperiphery of the member 49' of the lower adjustable eccentric device 63.

'I'he shaft 16 is normally biased in a counterclockwise direction, as seen in Fig. 3 by a torsion spring surrounding the shaft and having one end thereof secured to the shaft by a screw 8|. The opposite or free end portion of the spring projects laterally and bears against the under side of the cloth-plate l0. This bias of the shaft 16 is transmitted to the shaft 64 by the rockarm 15, link 13 and hand-lever 68. Thus the fingers 1l) and 19 of the arms 69 and 18, respectively, are normally maintained out of engagement with the apertures 1| and 1| in the members 48 and 48' of the adjustable eccentric devices 48 and 53.

When it is desired to vary the eccentricity of the eccentrics 48 and 63, the operator grasps the lever 68 and swings it upwardly. This movement simultaneously turns the shafts 64 and 18 clockwise, as seen in Fig. 3 and places the fingers 10 and 19 in lposition to enter the notches 1| and 1|', respectively. With the elements 49 .and 49' held against rotation by these fingers, the operator grasps the hand-wheel I1 and turns the shaft I6,

`which through the pulleys I9 and 2| and clipbelt 20, simultaneously and synchronously turns the shaft 22 and sleeve 22'. Angular movement of the shaft I8 and the locked shaft 22 and sleeve 22' unit relative to the members 49 and 49' varies Athe eccentricity of the eccentrics 48 and 63, as fully described in the above mentioned Myers Turning of the shaft I6 in one direction increases the eccentricity of the eccentrics 41 and 82 and thereby increases the length of work-feeding movement transmitted to the needles 21 and feedl-dog 5U. Turning of the shaft in the opposite direction has the opposite effect.

The hereinabove noted shaft 22 is journaled intermediate its ends in a bushing 82 carried in a lug 83 depending from the cloth-plate I0. The rear end portion of this shaft is disposed within the sleeve 22 which at its rear end, is joumaled within a ball bearing mounting 84 carried in a. lug 8-5 depending from the cloth-plate l0., 'Ihis rear end portion of the shaft 22 engages and is supported by the portion 85 of the sleeve 22. The forward end of the sleeve 22' terminates at Secured to the shaft 64, adjacent one' ra point within the eccentric device 83 and is sup hooks becomes jammed. By thus severing this connection, the unison feeding operation of the needles and lower feed-dog is continued while the rotary hooks remain stationary.

The pulley 2| comprises a pulley member 90 secured to the sleeve 22 by means of a set screw 9I and having the usual clip-belt slots 92 in the periphery thereof. Abutting both the end of the sleeve 22 and Aone edge of the hub of the pulley portion '90 is a collar 93 fixed to the outboard end of the shaft 22 by means of set screws 94. The collar 93 has a recess 95 with outwardly di-` vergent inclined sides, and a shouldered recess 96 in the periphery thereof.

Pivotally secured at one end by a screw 91 to the side face of the pulley portion 98 is a link 98 which is provided with a wedge-shaped projecltion 99, adapted to enter the recess 95 in the collar 93. The other end of the link 98 is pivotally connected by a pin to a second link |0I. The opposite end of the link |0I is pivoted to an arcuate spring` |92 by means of a pin |03. The other end of the arcuate spring is secured to the face of the pulley by a screw |04 and an intermediate portion I05 of the spring is adapted to engage a rim |08 of the pulley so as to function as a fulcrum.

The connected links 98 and IOI form a toggle mechanism. To break the toggle and reestablish driving relation, a pawl |01 is pivotally mounted on the pin |00. The pawl |01 is adapted to engage the shouldered recess 96 in the periphery of the collar 93. A light bow spring |08 yieldingly holds the pawl 01 in contact with the collar 93.v One end of the bow spring |08 is disposed within an aperture |09 provided inthe arcuate spring |02 and the opposite end of the bow spring has a bent portion I I0 bearing upon thepawl |01.

Olperatz'on Y The pulley 90 is driven in the direction indicated by the arrow in Fig. 4. When an excessive load or torque is applied to theshaft 22, theV wedge-shaped projection 99 is forced out of the recess 95 in the collar 93 by the inclined wall of the recess 95, thereby aligning the pivot points and straightening the toggle formed by members 98 and |0I, as shown in Fig. 6. Preferably, sumcient momentum is given the toggle when it is straightened to cause a slight reverse binding thereof, which is limited by the rim |06 of the 'pulley 90 which is `engaged by the projection III formed on the link 98. The effect of this slight reverse binding of the toggle is to move the wedge-shaped projection on the link 98 to a position out of contact with the collar 93, as shown in Fig. 6. When the wedge-shaped projection 99 on the link 98 is moved to a position out of contact with the collar 93, the spring-pressed pawl |01 which is pivoted to the toggle link 98 is moved outwardly with the link 98, and the free end 'of the pawl rides freely over the'periphery of the collar 93 in a counterclockwise direction as long as the driving memberfoverruns the driven member or shaft 22. It will be observed that the arcuate spring |02 acts inwardly in the direction of the collar 93 and the spring, therefore, tends to both straighten and break the toggle to effect the opening and closing of the clutch. It will be obvious that the maximum force required to straighten the toggle is at the beginning of the straightening operation, diminishing as the pivot points approach alignment.

When it is desired to reestablish driving relation, thepulley is manually rotated in the re'- verse direction.. When ,the shouldered recess 96 in the collar 93, engages the pawl |01 which is urged inwardly by the bow spring |08, the pivoted point or pin |00 of the toggle is pulled inwardly, breaking the toggle and thereby forcing the projection 99 on the link 98 into the wedgeshaped recess 95 in the collar 93. M

In order to lock the collar 93 while thus reengaging the clutch mechanism, there is provided on the present machine a locking disk ||2 which is secured upon the shaft 22 by means of a set screw II3 (see Fig. 1). riphery of this disk I2 is an aperture I I4 which is adapted to be entered by -a spring biased detent I|5 carried in the cloth-plate I0. A spring I I6 normally holds the detent I5 out of engagement with the disk II2. A shoulder II1 on the detent |I5 limits the upward movement thereof. Therefore, when the clutch mechanism is to be reengaged, the operator need only depress the detent I|5 and at the same time turn the handwheel I1 thereby to force the projection 99 back intothe collar recess 95.

" From the above description it is clear that whenever the rotary hooks become jammed, the clutch will open thereby releasing the shaft 22 from driving relation with the pulley 90. The sleeve 22' will continue to run and therefore the lower feeding mechanism will continue to operate in timed relation with the upper needle feed.

Having thus set forth the nature of the invention, what we claim herein is:

1v. In a sewing machine having a 'work-support, in combination, stitch-forming mechanism including a rotary loop-taker disposed below said work-support, a work-advancing feed-dog operating through said work-support, a feed-shaftv cluding a rotary loop-taker disposed below said work-support, a work-advancing feed-dog operating through said work-support, a tubular feedshaft rotatably journaled below said work-support, means for rotating said feed-shaft, means including operativeconnections with said feedshaft for actuating said-feeddog, a loop-taker actuating shaft rotatably journaled in said feedshaft, means comprising an overloadt release clutch for rotating said loop-taker actuating shaft from said feed-shaft, and driving connec Provided in the pe- A tions with said loop-taker actuating shaft for roy cluding a rotary loop-taker disposed below said Work-Support. a work-advancing feed-dog operating through said work-support, a. tubular feedshaft rotatably journaled below said work-supy port, means for rotating said feed-shaft, means operatively connected to said feed-shaft for imparting work-advancing and return movements to said feed-dog, an auxiliary shaft rotatably journaled in said feed-shaft, means comprising an overload release clutch for rotating said auxiliary shaft from said feed-shaft, means including operative connections with said auxiliary shaft for imparting rising and falling movements to said feeddog. and driving connections with said auxiliary shaft for rotating said loop-taker.

4. In a sewing machine having a work-support, in combination, stitch-forming mechanism including a rotary loop-taker disposed below said work-support, a work-advancing feed-dog operating through said work-support, a tubular feed-shaft rotatably journaled below said worksupport, an auxiliary shaft rotatably journaled in said feed-shaftand extending from opposite ends thereof, a pulley secured upon one end of said feed-shaft. driving connections for rotating said pulley, complemental overload release clutch elements carried by said pulley and one end of said auxiliary shaft, a feed-advance eccentric carried by said feed-shaft, a feed-lift eccentric carried by said auxiliary shaft, operative connections with said eccentrics for actuating said feed-dog, and driving connections with said auxiliary shaft for rotating said loop-taker.

work-advancing feed-dog operating through said work-support, means including operative connections with said tubular shaft for imparting workadvancing movements to said feed-dog, a rotary loop-taker disposed below said work-support and complemental to said needle in the formation of lock-stitches, and driving connections with said auxiliary yshaft for rotating said loop-taker,

7. In a sewing machine having a work-support, in combination, a thread-carrying needle, means for imparting endwise reciprocatory work-pene- 5. In a sewing machine having a frame including a work-support and an overhanging bracketarm, in combination. an arm-shaft extending lengthwise of and rotatably journaled in said bracket-arm, a tubular bed-shaft disposed substantially parallel to said arm-shaft and rotatably journaled at the under side of said worksupport, driving connections for rotating said shafts in unison, a thread-carrying needle, operative connections with said arm-shaft for imparting endwise reciprocatory work-penetrating and laterally vibratory work-feeding movements to said needle, a feed-dog operating through said work-support and provided with a needle-aperture, an auxiliary shaft rotatably journaled in said bed-shaft and extending from, opposite ends thereof, releasable coupling means comprising an overload release clutch connecting said bed and auxiliary shafts, means operatively connected to said bed-shaft for imparting work-advance and return movements to said feed-dog, means operatively connected to said auxiliary shaft for imparting rising and falling movements to said feed-dog. and driving connections with said auxiliary shaft for-rotating said loop-taker.

6. In a sewing machine having a work-support. in combination, a thread-carrying needle, means for imparting endwise reciprocatory work-penetrating and laterally vibratory work-feeding movements to said needle. a tubular shaft rotatably journaled at the under side of said worksupport, means including a driving member carried by one end of said tubular shaft for rotating said shaft, an auxiliary shaft rotatably journaled in said tubular shaft, means comprising an overload release clutch-link carried by said driving member and a clutch-collar canied by said auxiliary shaft lfor rotating said shafts in unison, a

trating and laterally vibratory work-feeding ably journaled at the under side of said worksuDpOrt, a belt-pulley secured upon one end of said tubular shaft, a feed-advance eccentric carried by the other end of said shaft, a feed-dog operating through said work-support and deriving work-advancing and return movements from said eccentric, an auxiliary shaft rotatably journaled in said tubular shaft, means comprising complemental overload release clutch elements carried by said pulley and auxiliary shaft for rotating said shafts in unison, a feed-lift eccentric carried by said auxiliary shaft, operative connections with said feed-lift eccentric for imparting rising and falling movements to said feed-dog, a rotary loop-taker complemental to said needle in the formation of stitches, and driving connections with said auxiliary shaft for rotating said loop-taker.

8. In a sewing machine, in combination, a work-support, stitch-forming mechanism including a thread-carrying needle and a rotary loop-taker, concentrically arranged rotary actuating shafts disposed below said work-support, driving connections including an overload release clutch between said shafts, work-feeding mechanism, operative connections with one of said rotary shafts for actuating said work-feeding mechanism, and operative connections with the other of said shafts for rotating said loop-taker.

9. In a sewing'machine having a work-support. in combination, stitch-forming mechanism including a rotary loop-taker disposed below said work-support, a work-advancing feed-dog operating through said work-support, a tubular feedshaft rotatably journaled below said work-support, operative connections between said feeddog and said tubular feed-shaft, an auxiliary shaft rotatably journaled in said feed-shaft and extending from opposite ends thereof; operative connections between said loop-taker and said auxiliary shaft, a pulley secured upon one end of said feed-shaft, means for rotating said pulley, driving connections including an overload release clutch between said pulley and said auxiliary shaft, said clutch being adapted to disconnect said pulley and said auxiliary shaft whenever a predetermined load is applied to said auxiliary shaft, and means for reconnecting said pulley and said auxiliary shaft through said clutch, 'said' latter means including a manually controllable locking device associated with said auxiliary shaft and adapted for locking said latter shaft against rotary movement. v

10. In a sewing machine having a frame `including a work-support and an overhanging bracket-arml in combination, an arm-shaft rotatably journaled in said bracket-arm, a threadcarrying needle, operative connections -with said arm-shaft for imparting endwise reciprocatory work-support, driving connections for rotating said shafts in unison, a rotary loop-taker disposed below said work-support and complemental to said needle in the formation of lock-stitches, a rotary loop-taker actuating shaft disposed within said tubular bed-shaft, driving connections including an overload release -clutch between said tubular bed-shaft and said loop-taker actuating shaft', work-feeding mechanismdisposed below said work-support, and positive driving connections between said tubular bed-shaft and said work-feeding mechanism for imparting work-advancing movements to said latter mechanism in unison with the work-advancing movements of said needle.

11. In -a sewing machine having a. frame including a. work-supportv and an overhanging bracket-arm, in combination, an arm-shaft extending lengthwise of and rotatably journaled in said bracket-arm, a thread-carrying needle, operative connections with said arm-shaft for imparting endwise reciproca-tory work-penetrating and laterally vibratory Work-feeding maffements to said needle, a tubular bed-shaft rotatably journaled at the under side of said worksupport, a pulley mounted upon one end of said bed-shaft, driving connections between said armshaft and said pulley for rotating said shafts inunison, work-feeding mechanism disposed below said work-support, means including an eccentric mounted upon theother end of said tubular bedshaft for actuating said work-feeding mechanism in unison with the work-advancing movements of said needle, an auxiliary shaft rotatably journaled in said tubular bed-shaft and extending from opposite ends thereof, releasable coupling means comprising an overload release clutch connecting said bed-shaft and one exposed portion of said auxiliary shaft, a rotary loop-taker disposed below said work-support, and means carried upon the oppositelyexposed portion of said auxiliary shaft forA actuating said loop-taker.

12. In a sewing machine, in combination, a Work-support, stitch-forming mechanism including a thread-carrying needle and a rotary looptaker, a tubular feed-shaft, a rotary loop-taker actuating shaft extending through said tubular feed-shaft, driving connections including an overload release clutch between said shafts,

work-feeding mechanism operatively connectedv to said tubular feed-shaft, and operative connections between said loop-taker actuating shaft andvsaid rotary loop-taker.

13. In a sewing machine having a work-support,

in combination, stitch-forming mechanism in `shaft for actuating said feed-dog, a rotary looptaker actuating shaft extending through said.

tubular feed-shaft, means comprising an overload release clutch for rotating said loop-taker actuating shaft from said feed-shaft, and driving connections with said loop-taker actuating shaft for rotating said loop-taker.

FRANK PARRY.

BERTHOLD P. PINKVOSS.' 

